The present invention relates to a testing apparatus and a method for performing an electrical characteristic test for a test piece, particularly, to a testing apparatus and a method for performing an electrical characteristic test, e.g., a reliability test such as a burn-in test, for an electronic part having a large number of electronic circuits formed on the surface. To be more specific, the present invention relates to a wafer collective testing apparatus and a method for applying a reliability test such as a burn-in test, which is applied to a plurality of semiconductor devices, i.e., an IC chip, to an IC chip as formed on a semiconductor wafer. The present invention also relates to a contactor used for testing the electrical characteristics of a test piece and a method of manufacturing the same, more particularly, to a contactor that is collectively brought into contact with the test piece in performing the test and a method of manufacturing the same.
The electrical characteristics of each of a large number of IC chips formed on the surface of a wafer are tested in a process of testing a semiconductor device. IC chips free from defects are screened on the basis of the test results. The screened good IC chips are packaged with a synthetic resin or a ceramic material in the assembling process. In a burn-in test that is one of reliability tests, thermal and electrical stresses are applied to the packaged IC chip to make the latent defects of the IC chip visible.
With progress in miniaturization and required performance of various electrical appliances, the IC chip is also miniaturized and the degree of integration of the IC chip is promoted. Also, with progress in the operating speed of the electrical appliances, high frequency characteristics of 100 MHz to 300 MHz are required in the logic circuit or the memory circuit.
Recently, various mounting techniques have been developed for further miniaturization of the semiconductor device. Particularly, a technique in which an IC chip is not packaged, e.g., a flip chip mounting technique in which a so-called bare chip is mounted to an electrical appliance, is being developed. As a result of development of the particular technique, a quality-guaranteed KGD has come to be put on the market. In this case, the quality as KGD must be guaranteed by applying a burn-in test (reliability test) as a final test to each IC chip.
A technique for testing the reliability of an IC chip as formed on a wafer is proposed in, for example, Japanese Patent Disclosure (Kokai) No. 7-231019, Japanese Patent Disclosure No. 8-5666 and Japanese Patent Disclosure No. 8-340030. Particularly, the former two prior arts propose a technique for collectively bringing a wafer into contact with a contactor without fail while eliminating the thermal effect in performing a reliability test. In testing the reliability of the IC chip as formed on a wafer surface, it is very important to bring collectively the wafer into contact with a contactor at a high accuracy under high temperatures in order to ensure reliability of the burn-in test.
A probe card is used as a contactor in testing the electrical characteristics of an IC chip having a large number of memory circuits, logic circuits, etc. formed on a wafer. The probe card includes a plurality of probe terminals arranged to correspond to, for example, the positions of a plurality of electrode pads formed on the IC chip. During the test, the probe terminals of the probe card are electrically brought into contact with the electrode pads to play the role of relaying the testing signal and information on the result of the test between a tester and the IC chip. The probe terminal is formed of, for example, a tungsten wire or a pogo pin.
Recently, the number of electrode pads is rapidly increased with improvement in the degree of integration of IC chips. As a result, the pitch of arranging the electrode pads becomes narrower and narrower. Naturally, the number of probe terminals of the probe card is also increased rapidly, with the result that the probe terminals are arranged at a smaller pitch.
However, in a conventional wafer collective testing apparatus used for the reliability test, a long electrical connecting wire is used for connecting a pattern signal generating circuit mounted to the tester to the contactor. However, the pattern signal for the testing generated from the pattern signal generating circuit is electrically affected while transmitted through the long connecting wire, making it very difficult to test the reliability of the high speed IC chip under the actual operating speed. Therefore, in the conventional reliability test, it was necessary to test the reliability at an operating speed, e.g., about 1 to 10 MHz, at which the electrical influence is not given by the connecting wire.
Concerning the contactor, a plurality of probe terminals are manually mounted to a substrate. It should be noted in this connection that the number of probe terminals is increased nowadays as described previously, making it difficult to align manually the positions for mounting very small probe terminals at a small pitch and to mount manually the probe terminals. It follows that it is difficult to manufacture the contactor itself. In addition, the probe terminal made of a tungsten wire involves a limitation in the mounting structure, making it difficult to arrange the probe terminals to correspond flexibly to the arrangement of the testing electrode pads for the test piece. Incidentally, a technique relating to a contactor having probe terminals arranged at a small pitch is disclosed in, for example, Japanese Patent Disclosure No. 5-198636, Japanese Patent Disclosure No. 5-218156 or Japanese Patent Disclosure No. 10-38918.
An object of the present invention is to solve the above-noted problems inherent in the conventional technique.
To be more specific, the present invention is intended to provide a collective testing apparatus for a test piece and a testing method, which permit conducting a test for electrical characteristics, i.e., a reliability test, of a test piece under an actual operating speed without receiving electrical influences given by the connecting wiring between a tester and a contactor even if the test piece operates at a high speed.
The present invention is also intended to provide a contactor, which can be made to correspond flexibly to the arrangement of the testing electrode pads of a test piece, which permits automatically mounting the probe terminals, and which also permits the probe terminals to be brought into contact satisfactorily with the electrode pads of the test piece so as to improve the accuracy of the test, and to provide a method of manufacturing the contactor.
According to a first aspect of the present invention, there is provided a testing apparatus for testing the electric characteristics of a plurality of circuit elements formed on a test piece, comprising:
a chuck for supporting a test piece having a plurality of test electrodes formed on the surface;
a tester for generating a control signal relating to an electrical characteristic test of a plurality of circuit elements formed on the test piece and for testing the electrical characteristics of the circuit elements based on the test result information generated from the circuit elements; and
a contactor including a plurality of probe terminals that are collectively brought into contact with at least some of the test electrodes, a test pattern signal generating circuit for generating a test pattern signal in accordance with the control signal transmitted from the tester, a first electric connection wiring arranged between the test pattern signal generating circuit and the probes for transmitting the test pattern signal generated from the test pattern signal generating circuit to the probes, and second electric connection wirings for outputting the test result information generated from the circuit elements to the tester via the probe terminals.
In the testing apparatus of this embodiment, it is desirable for the test piece to consist of a plurality of IC chips formed on a semiconductor wafer.
It is also desirable for the testing apparatus to comprise further a pushing mechanism for pushing the contactor toward the test piece held on the chuck to bring the contactor into contact with the chuck.
It is also desirable for the contactor of the testing apparatus to further includes a contactor substrate on which the probe terminals are mounted and a holder for holding the contactor substrate.
It is also desirable for the contactor of the testing apparatus to further includes a clock circuit for generating a clock signal whose frequency can be varied, and for the test pattern signal generating circuit to generate a test pattern signal in accordance with the clock signal generated from the clock circuit.
It is also desirable for the contactor of the testing apparatus to further include a comparator circuit for comparing the test result information generated from the circuit elements with an expected value pattern signal to determine whether the electrical characteristics of the circuit element are good or not.
It is also desirable for the contactor of the testing apparatus to further include a register for temporarily storing the test result information generated from the circuit elements, and a comparator circuit for comparing the test result information supplied from the register with an expected value pattern signal so as to determine whether the electrical characteristics of the circuit element are good or not.
It is also desirable for the chuck and the contactor to be arranged within a test piece housing body for housing the test piece.
According to a second aspect of the present invention, there is provided a testing apparatus for testing the electrical characteristics of a plurality of circuit elements formed on a test piece, comprising:
a chuck for supporting a test piece having a plurality of test electrodes formed on the surface;
a tester for generating a control signal relating to an electrical characteristic test of a plurality of circuit elements formed on the test piece and for testing the electrical characteristics of the circuit elements based on the test result information generated from the circuit elements;
a contactor including a plurality of probe terminals that are collectively brought into contact with at least some of the test electrodes; and
an electrical connection body for electrically connecting the contactor and the tester, the electrical connection body including a test pattern signal generating circuit for generating a test pattern signal in accordance with the control signal supplied from the tester.
In the testing apparatus of this embodiment, it is desirable for the test piece to consist of a plurality of IC chips formed on a semiconductor wafer.
It is also desirable for the contactor of the testing apparatus to include a contactor substrate having the probe terminals mounted thereto and a holder for holding the contactor substrate.
In the testing apparatus of this embodiment, it is also desirable for the electrical connector to be arranged to surround the outer circumferential surface of the chuck.
In the testing apparatus of this embodiment, it is also desirable for the electrical connector to be arranged separately from the chuck and the contactor.
In the testing apparatus of this embodiment, it is also desirable for the electrical connector to further include a clock circuit for generating a clock signal whose frequency can be varied, and for the test pattern signal generating circuit to generate a test pattern signal in accordance with the clock signal generated from the clock circuit.
In the testing apparatus of this embodiment, it is also desirable for the electrical connector to further include a comparator circuit for comparing the test result information generated from the circuit elements with an expected value pattern signal to determine whether the electrical characteristics of the circuit element are good or not.
In the testing apparatus of this embodiment, it is also desirable for the electrical connector to further include a register for temporarily storing the test result information generated from the circuit elements, and a comparator circuit for comparing the test result information supplied from the register with an expected value pattern signal so as to determine whether the electric characteristics of the circuit elements are good or not.
In the testing apparatus of this embodiment, it is also desirable for the chuck and the contactor to be arranged within a test piece housing body for housing the test piece.
According to a third aspect of the present invention, there is provided a method of testing electrical characteristics of a test piece, comprising the steps of:
collectively bringing the probe terminals of a contactor into contact with at least some of a plurality of test electrodes of a test piece disposed on a chuck;
allowing a control signal relating to an electrical characteristic test of the test piece to be generated from a tester and transmitting the control signal to a test pattern signal generating circuit mounted to the contactor;
allowing a test pattern signal to be generated from the test pattern signal generating circuit in accordance with the control signal supplied from the tester;
applying the test pattern signal to the test piece through the probe terminal;
outputting the test result information generated from the test piece to the tester through the probe terminal; and
testing the electrical characteristics of the test piece in the tester based on the test result information.
In the method of the present invention, it is desirable for the test piece to consist of a plurality of IC chips formed on a semiconductor wafer.
According to a fourth aspect of the present invention, there is provided a method of testing electrical characteristics of a test piece, comprising the steps of:
collectively bringing the probe terminals of a contactor into contact with at least some of a plurality of test electrodes of the test piece disposed on a chuck;
allowing a control signal relating to the electrical characteristic test of the test piece to be generated from a tester, and transmitting the control signal to a test pattern signal generating circuit mounted to an electric connector for electrically connecting the contactor and the tester;
allowing a test pattern signal to be generated from the test pattern signal generating circuit in accordance with the control signal generated from the tester;
applying the test pattern signal to the test piece through the probe terminal;
outputting the test result information generated from the test piece to the tester through the probe terminal; and
testing the electrical characteristics of the test piece in the tester based on the test result information.
According to a fifth aspect of the present invention, there is provided a contactor, comprising:
a contactor substrate including a plurality of terminal holes, a conductive layer formed on the inner circumferential surface of each terminal hole, and a wiring layer electrically connected to the conductive layer;
a probe terminal having the proximal end portion inserted into a predetermined one of the terminal holes and electrically connected to the conductive layer; and
a holder for holding the contactor substrate.
In the contactor of the present invention, it is desirable for grooves extending in at least two opposite directions to be formed alternately on the side surface of a distal end portion, which is exposed to the outside of the terminal hole, of the probe terminal.
In the contactor of the present invention, it is also desirable for the proximal end portion of the probe terminal inserted into the terminal hole to be in the shape of a trapezium that is tapered upwardly.
In the contactor of the present invention, it is also desirable for the contactor substrate to further include a test pattern signal generating circuit for generating a test pattern signal in accordance with a control signal supplied from a tester.
In the contactor of the present invention, it is also desirable for the contactor substrate to include at least one temperature sensor mounted to that surface on which the probe terminal is mounted.
In the contactor of the present invention, it is also desirable for the contactor substrate to include a heat transmitting medium mounted to that surface on which the probe terminal is mounted.
According to a sixth aspect of the present invention, there is provided a method of manufacturing a contactor, comprising the steps of:
forming a plurality of terminal holes on a surface of a contactor substrate;
forming a conductive layer on the inner circumferential surface of each of the terminal holes, and forming a wiring layer electrically connected to the conductive layer; and
inserting a probe terminal into a predetermined one of the terminal holes.
In the method of the present invention, it is desirable for the step of inserting the probe terminal into the terminal hole to include the process of successively detaching a predetermined number of probe terminals from a probe terminal member having a plurality of probe terminals joined to each other and pushing the detached probe terminal into the terminal hole.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.